DISASTER HAZARDS IN BHUTAN By Tshewang Rinzin 26-27 January 2009 Reducing Disaster Risks for a Safe and Happy Bhutan
Disaster Hazards in Bhutan Earthquakes Glacial Lake Outburst Flood (GLOF) Floods in monsoon Natural Dam formation and dam bursts Landslides Fires Droughts Epidemics, Pests, Diseases
Earthquakes Bhutan is located in one of the most active seismic zones ( Zones IV &V) 8+ RS: 1897, 1906, 1934 7+RS: 1713, 1806, 1947 6+RS: 1910, 1941, 1950, 1954, 1960, 1980, 1988 5+RS: 2003, 2006
Glacial Lake Outburst Flood (GLOF) GLOFs: the most serious natural hazard potentials with 25 lakes potentially dangerous out of about 3000 glacier lakes.. Hazards due to GLOF flash floods are likely to increase in intensity with the impacts of climate change.
Glacial Lakes form due to glacial melt/retreat Global warming has accelerated glacial retreat, and therefore the formation/expansion of glacial lakes. Using current technology, GLOFs can neither be totally prevented nor predicted. Home Minister in his speech on 20/1/2009 called it SILENT TSUNAMIS
Lugge Tsho 1993, SPOT
Thorthormi Tsho 1993, SPOT
Cases of major Glacial Lakes from Lunana (Bhutan Himalaya) Raphsthreng Tsho 1993, SPOT
Interconnected glacier and glacial lake systems. Google Earth 2008 Rephstreng Thorthormi Luggye
Thorthormi Potentially dangerous? Size of glacier (3.422 sq. Km) Google Earth 2008 Lake III Lake I Lake II Thorthormi
Thorthormi Potentially dangerous? Formation of large supra-glacial lakes DGM 2007 DGM 2007 Rapid extension of the supra-glacial lakes due to fast glacial melting. 1968 2001, ICIMOD 2005 2006, DGM
Thorthormi Potentially dangerous? Thinning barrier between Thorthormi and Raphstreng Change in barrier width i. 75 m in 2006 ii. 46.80 m in 2007 (from DGM annual Lunana reports) Thorthormi Tso 46.80 m Rephstreng Tso
Change in Glacier Oct. 1984 Oct. 1999
Change in Glacier Oct. 1984 Oct. 1999
Major GLOF incidences1957, 1960 and most recently 1994 The 1994 GLOF caused 21 lives and damaged more than 1700 acres of land.
GLOFs threaten lives and livelihood of people living in the valleys and low lying river plains.
The basins of Mochu, Po chu, Mangde chu, Chamkhar chu and Kuri chu pose threats to the lives, livelihoods of people living in the valleys and low lying river plains Po Chu Mo Chu Maghde Chu chamkar Chu Kurichu
Potentially dangerous glacial lakes of Bhutan Pho Chu Sub Basin : 9 Mo Chu Sub Basin : 5 14 Chamkhar Chu Sub Basin: 3 Kuri Chu Sub Basin: 1 Mangde Chu Sub Basin: 7 Out of 2794 glacial lakes, 25 has been identified as potentially dangerous lakes. Source: DGM & ICIMOD publication
Source: Survey of Bhutan Over 70% of the settlements are located along the drainage basins.
1994 1994 1999 Raphstreng and glacier tongue of Thorthormi Glacier Sat imagery: 1994 and 1999
The Chamkhar chu Basin
Chubda Tso (Chamkhar Chu Sub Basin
Floods Recurrent phenomena in Bhutan Killed 49 people and destroyed 17 houses in Pasakha. 2004 monsoon in eastern Districts have caused loss: 9 lives, 29 houses, and 664 acres of land. The most recent flash floods of Phuentsholing and Pasakha have caused 49 lives and destruction to 17 houses.
Natural Dam formation and dam bursts In September 2003, there was a dam formation at Tsatichhu which burst its banks in July 2004 releasing 6000 cubic meters per second There are also transboundary threats due to such dam formations
Natural Dam formation and dam bursts Such hazards will continue to prevail in Bhutan s rivers placing many of the hydropower plants, farmland and human settlements at risk.
Landslides Slopes in the country highly susceptible to landslides during rainy season.
Landslides Most occur in the eastern and southern foothills belt where the terrain is steep and rocks underlying the soil cover are highly fractured, allowing easy seepage of water.
Fires on forest and human settlements: A total of 803 forest fires damaging 309,181.9 acres of forest were recorded from 1994-2004. In 2002, 25 houses in Yangthang village in Haa were burnt. In 2005, 5 houses in Bumthang were burnt March 2006, forest fire in Bartsham destroyed five houses and killed 3 people.
Epidemics, Pests and Diseases: Avian flu and other diseases An influenza pandemic is a unique event Once a fully transmissible pandemic virus emerges, its international spread is considered unstoppable Through trade in poultry and poultry products The migratory water birds Damages to crops by wild animals etc
Ongoing Efforts Disaster Management Committee as in place right to the village level Improvement of early warning system in case of GLOF Mitigation work amounting to US$ 7.8 million to start soon (draining out water through channels with regulated discharge
Thank you for your Attention TASHIDELEK